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Post Info TOPIC: International Astronomical Union


L

Posts: 131433
Date:
New Planets
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3 new planets, 2 of them are plutons:



1) Ceres
2) Charon
3) 2003 UB313


12 planet candidates:



1) 2003 EL 61
2) 2005 FY 9
3) Sedna
4) Orcus
5) Quaoar
6) 2002 TX 300
7) 2002 AW 197
8) Varuna
9) Ixion
10) Vesta
11) Pallas
12) Hygiea

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L

Posts: 131433
Date:
12 proposed planets?
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The universe really is expanding - astronomers are proposing to rewrite the textbooks to say that our solar system has 12 planets rather than the nine memorized by generations of schoolchildren.
Much-maligned Pluto would remain a planet - and its largest moon plus two other heavenly bodies would join Earth's neighbourhood - under a draft resolution to be formally presented Wednesday to the International Astronomical Union, the arbiter of what is and isn't a planet.

"Yes, Virginia, Pluto is a planet" - Richard Binzel, a professor of planetary science at the Massachusetts Institute of Technology.

The proposal could change, however: Binzel and the other nearly 2,500 astronomers from 75 nations meeting in Prague to hammer out a universal definition of a planet will hold two brainstorming sessions before they vote on the resolution next week. But the draft comes from the IAU's executive committee, which only submits recommendations likely to get two-thirds approval from the group.
Besides reaffirming the status of puny Pluto - whose detractors insist it shouldn't be a planet at all - the new lineup would include 2003 UB313, the farthest-known object in the solar system and nicknamed Xena; Pluto's largest moon, Charon; and the asteroid Ceres, which was a planet in the 1800s before it got demoted.
The panel also proposed a new category of planets called "plutons," referring to Pluto-like objects that reside in the Kuiper Belt, a mysterious, disc-shaped zone beyond Neptune containing thousands of comets and planetary objects. Pluto itself and two of the potential newcomers - Charon and 2003 UB313 - would be plutons.
Astronomers also were being asked to get rid of the term "minor planets," which long has been used to collectively describe asteroids, comets and other non-planetary objects. Instead, those would become collectively known as "small solar system bodies."
If the resolution is approved, the 12 planets in our solar system listed in order of their proximity to the sun would be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon, and the provisionally named 2003 UB313. Its discoverer, Michael Brown of the California Institute of Technology, nicknamed it Xena after the warrior princess of TV fame, but it likely would be rechristened something else later.

The new proposal would force publishers to update encyclopaedias and school textbooks, and elementary school teachers to remake the planet mobiles hanging from classroom ceilings. Far outside the realm of science, astrologers accustomed to making predictions based on the classic nine might have to tweak their formulas.
Even if the list of planets is officially lengthened when astronomers vote on August 24, it's not likely to stay that way for long: The IAU has a "watchlist" of at least a dozen other potential candidates that could become planets once more is known about their sizes and orbits.

"The solar system is a middle-aged star, and like all middle-aged things, its waistline is expanding" - Jack Horkheimer, director of the Miami Space Transit Planetarium in the United States and host of Public Broadcasting's Stargazer television show.

Opponents of Pluto, which was named a planet in 1930, still might spoil for a fight. Earth's moon is larger; so is 2003 UB313 (Xena), about 70 miles wider.
But the IAU said Pluto meets its proposed new definition of a planet: any round object larger than 800 kilometres in diameter that orbits the sun and has a mass roughly one-12,000th that of Earth. Moons and asteroids will make the grade if they meet those basic tests.
Roundness is key, because it indicates an object has enough self-gravity to pull itself into a spherical shape. Yet Earth's moon wouldn't qualify because the two bodies' common centre of gravity lies below the surface of the Earth.

"People were probably wondering: If they take away Pluto, is Rhode Island next? "There are as many opinions about Pluto as there are astronomers. But Pluto has gravity on its side. By the physics of our proposed definition, Pluto makes it by a long shot" - Richard Binzel

IAU President Ronald D. Ekers said the draft definition, two years in the making, was an attempt to reach a cosmic consensus and end decades of quarrelling.

"We don't want an American version, a European version and a Japanese version" - Ronald D. Ekers.

Neil deGrasse Tyson, director of the Hayden Planetarium at New York's American Museum of Natural History - miscast as a "Pluto-hater," he contends, merely because Pluto was excluded from a solar system exhibit - said the new guidelines would clear up the fuzzier aspects of the Milky Way.

"For the first time since ancient Greece, we have an unambiguous definition. Now, when an object is debated as a possible planet, the answer can be swift and clear" - Neil deGrasse Tyson.

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L

Posts: 131433
Date:
Definition of a Planet
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Scientists have to agree on a universal definition for what qualifies as a planet, the head of a global astronomy organisation said Tuesday, as scientists debate the future designation of Pluto.

"People have to be able to agree on a terminology that's used to describe things in the universe. We don't want an American version, a European version and a Japanese version" - Ronald D. Ekers, president of the International Astronomical Union, told reporters in Prague.

Ekers made his comments on the sidelines of a meeting of nearly 2,500 astronomers from 75 countries. During the 12-day conference, which began Monday, scientists were expected to work on finding an internationally accepted definition of what constitutes a planet, and decide whether Pluto should keep its status. Scientists were also expected to consider whether to bring a new planet, nicknamed Xena, into the fold, possibly along with dozens more.

"This particular definition, the definition of a planet, is one that of course has huge public interest" - Ronald D. Ekers.

For decades, most people have defined our solar system as having nine planets, though some have questioned whether Pluto - smaller than Earth's moon - belonged in that category. The discovery last year of an object larger and further away than Pluto has thrown cosmic definitions into chaos.
Until now, there have been no definitive criteria, with most simply describing a planet as a large, round object that orbits the Sun. Scientists will work on establishing criteria for planet status - including the object's mass, orbit and distance from the Sun - and then whether Pluto and Xena meet the definition.
Depending on the results, to be announced at the end of the conference, the solar system could be expanded to include 23, 39 or even 53 planets. If the newly found Xena qualifies as a planet, some argue, so should several other bodies found in the outer reaches of the solar system. Others say, however, that if Xena is ruled out as a planet, Pluto should be as well.
A third group of scientists has suggested that planets be classified into categories based on composition, similar to the way stars and galaxies are classified. Jupiter could be labelled a "gas giant planet," while Pluto and Xena could be "ice dwarf planets."

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L

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RE: International Astronomical Union
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Astronomer Thomas Marquart has created a blog about the International Astronomical Union meeting.

http://astronomy2006.blogspot.com/

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L

Posts: 131433
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Pluto the Ninth, Xena (2003 UB313) the Tenth, and brighter than Pluto after that

The regular asteroid observers, including amateur astronomers, are doing well with their CCDs in faint follow-up astrometry. However, large wide-angle telescopes and special equipment are needed to explore the outer solar system, including the rare objects that might qualify as planets. The searching is done with expensive telescopes by experts who are not always asteroid observers. The greatest encouragement for exploration of the outer solar system is the excitement that a new Planet might be found. Observatory directors and funding agencies are well aware of that.
This proposal is therefore to stay with the 75 years of popularly considering Pluto the Ninth, as the IAU agreed to in Manchester, and to adopt Xena as the Tenth Planet because it is intrinsically brighter than Pluto. The proposal is further that the same accurate and convenient criterion be used for naming an Eleventh Planet and so forth, namely that they be intrinsically brighter than Pluto, measured in “absolute V-magnitude.” Pluto's absolute visual magnitude is –0.76, Xena's –1.2. The present proposal is written on behalf of people who are doing the observing and discovering, who see the need for prompt recognition and the fastest return in naming. This has been explained before, in Nature 436, 1088, 2005 and Sky & Tel. 111, No. 1, 14, 2006, and this Letter has been circulated in draft form, but there has been no response from the two naming committees of the IAU. Considering roundness due to gravitational stability is complex, time consuming, subject to change, and impossible due to faintness at great distance.
A compromise for proper study and distinction of the various objects and populations is to attach to Pluto and to any new Planets also the usual comet or asteroid designation. Xena already has 2003 UB313, which eventually will be a 6-digit catalogue number. The dual assignment, as Planet and comet or asteroid, will also stimulate discussion in schools and colleges of the rich variety of solar-system objects.

Source

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L

Posts: 131433
Date:
Prague Congress Centre
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Prague Congress Centre
Expand (103kb, 800 x 503)
Latitude 50.061920°N, Longitude 14.428769°E

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L

Posts: 131433
Date:
RE: International Astronomical Union
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IAU General Assembly 2006 News

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L

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Astronomers are gathering in the Czech capital, Prague, hoping to define exactly what counts as a planet.

The International Astronomical Union hopes to settle the question of Pluto, which was first spotted in 1930.
Experts are divided over whether Pluto - further away and considerably smaller than the eight other planets in our solar system - deserves the title.
The stakes were raised when a bigger planet-type body, known as 2003 UB313, was discovered by a US astronomer.
Professor Mike Brown and colleagues at the California Institute of Technology have discovered several other planetary objects in an area at the edge of the solar system known as the Kuiper Belt.
Now delegates to the Prague conference are being asked to agree on a formal definition of what is a planet for the first time.

Source

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L

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After 39 years the IAU returns to Prague and it is my great pleasure to invite you to attend this twenty-sixth General Assembly which will be taking place from August 14 to 25, 2006. 39 years is only a brief moment in Prague’s great astronomical history but it’s half the lifetime of the IAU.

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The International Astronomical Union (IAU) was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Its individual members are professional astronomers all over the World, at the Ph.D. level or beyond and active in professional research and education in astronomy. However, the IAU maintains friendly relations also with organisations that include amateur astronomers in their membership. National Members are generally those with a significant level of professional astronomy. The IAU is composed of 8,858 Individual Members in 85 different countries worldwide out of which 62 are National Members (according to statistics of August 2006).

The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and any surface features on them.

www.iau.org/

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